Application of chiral, cyclic sulfinamides

The reduced proportion of (24) observed when employing organolithium reagents can also be rationalized, since the lithium cation is monovalent and therefore cannot form species such as (26). Since, in this procedure, both nucleophilic groups add consecutively with inversion of configuration, the configuration of the final sulfoxide product (25) is dependent upon the order of addition of the attacking nucleophiles. 

There are three main disadvantages with the method developed by Wudl and Lee  

Epimerization at sulfur, proposed to occur through sulfinyl transfer, reduces the diastereoselectivity of the initial displacement reaction. 

Final displacement to yield the required sulfoxides occurs in good yield only with organolithium reagents, but is accompanied by significant racemization. The use of Grignard reagents eliminates racemization but results in lower yields. 

Two equivalents of organometallic reagent are required for the final displacement reaction. One equivalent is consumed in deprotonation of the hydroxy group of the hydroxysulfinamide. 

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